Abstract

Frying oils is daily need to fry the foods. The use of frying oils frequently is harmful for our
health and waste of frying oils contaminate environment. The quality of used frying oils can
be improve by adsorption process with citric acid as adsorbent. Research conducted on using
citric acid (1 and 2 %w) , temperature (50 and 80°C) and mixing time (1 hour and 2 hours) at
mixing rate 500 rpm. The response data of the research are Fe content, FFA value, peroxide
value, linoleneic acid value and water content. Analysis of data was done by design expert
software, then do the optimation process. The results shows that adsorption process of used
frying oils with citric acid can reduce Fe content and peroxide value, increase lenoleneic acid
value, but can’t interfere FFA and water content significantly. Significant variable for
reducing Fe are citric acid concentration (A), mixing time (B), temperature (C) and
interaction between variable B and C (BC), then for reducing peroxide acid are acid
concentration (A) and temperature (C) and for increasing linoleneic acid are citric acid
concentration (A), mixing time (B), temperature (C). optimum variables for reducing peroxide
value can be obtain at citric acid concentration 2 %w, mixing time 1 hours and temperature
65°C. These condition can reduce peroxide acid value until 8 meqO2/kg oils from initial
condition 30,096 meqO2/kg.